The PICTURE-C exoplanetary direct imaging balloon mission: first flight preparation

Abstract

The Planetary Imaging Concept Testbed Using a Recoverable Experiment - Coronagraph (PICTURE-C) mission will directly image debris disks and exozodiacal dust around nearby stars from a high-altitude balloon using a vector vortex coronagraph. The first flight of PICTURE-C launched from the NASA Columbia Scientific Balloon Facility in Ft. Sumner, NM on September 28, 2019 and ew for a total of 20 hours, with 16 hours at oat altitude above 110,000 ft. This flight successfully demonstrated many key technologies for exoplanetary direct imaging missions and all hardware components for the second, science-focused flight of PICTURE-C scheduled for the fall of 2021. These technologies include a vector vortex coronagraph, high and low-order deformable mirrors and a high speed low-order wavefront control system. The experiment also demonstrated a 60 cm off-axis telescope with a hexapod-actuated secondary mirror that aligned itself automatically during flight. This paper details the ight performance of PICTURE-C, focusing on the operation of the low-order wavefront control system and the influence of high-frequency structural vibrations. We present new structural modifications that have been made to reduce these vibrations and laboratory demonstrations of the ight 2 coronagraph, which uses a high-order 952 actuator MEMS deformable mirror to create a high-contrast dark zone.